/Engine/Source/Runtime/SignalProcessing/Public/DSP/Envelope.h
Generates an output audio buffer (used for audio-rate envelopes)
void GetNextEnvelopeOut ( int32 StartFrame, int32 EndFrame, [TArray](API\Runtime\Core\Containers\TArray)< int32 > & OutFinishedFrames, [Audio::AlignedFloatBuffer](API\Runtime\SignalProcessing\DSP\AlignedFloatBuffer) & OutEnvelope )